porter create command should create directory with bundle files included

[phillipgibson]

What design is being proposed?
When using porter create , the command will create all the files associated with the bundle in the current directory where ran. For a cleaner file system organization, a directory of the bundle name should be made with the files for the bundle created in that directory.

Additional Context
This functionality saves a step for the user. An example of this is how Rust uses the cargo new command.

Risks/Concerns
None that I'm aware of.

What other approaches were considered?
None

Implementation details
portal create mybundle
cd mybundle
ls - porter.yaml, README.md template.Dockerfile, etc.

Checklist

• An announcement of this proposal has been sent to the Porter mailing list: https://getporter.org/mailing-list
• This proposal has remained open for at least one week, to allow time for community feedback.

[schristoff]

This functionality is also how helm create works, for anyone taking a peek at this issue it may be good to pull inspiration from their implementation here

[sbdtu5498]

/assign